NSW Health has detected COVID-19 fragments in the South Windsor sewage system, and four new cases have been identified in the Penrith Local Government Area (LGA).
South Windsor sewage treatment plant serves about 19,000 people in suburbs including Windsor Downs, Bligh Park, Clarendon and South Windsor.
NSW Health is particularly concerned by this detection, as there are no known cases in this area.
Of the 170 locally acquired cases reported to 8pm last night, 87 are from South Western Sydney LHD, 32 are from Western Sydney LHD, 32 are from Sydney LHD, 13 are from South Eastern Sydney LHD, four are from Nepean Blue Mountains LHD - which includes Penrith - and two are from Northern Sydney LHD.
Penrith LGA now has 26 cases with seven from an unknown source.
Blacktown LGA cases rose to 153 from 146 yesterday.
There were two new cases in The Hills Shire, bringing the total for that region to 22.
Hawkesbury numbers remained stable at six cases and Blue Mountains remained stable at two cases.
If you have any symptoms, get tested. Testing locations can be found at https://www.nsw.gov.au/covid-19/health-and-wellbeing/clinics